For inflating tires with compressed air, the automatic series production of automotive vehicle wheels with tubeless tires uses automatic tire inflation devices of the type known from U.S. Pat. Nos. 6,467,524 B2 and 7,506,671 B2 which are integrated into the assembly line. In such devices, the wheel rim with the fitted tire is placed on a suitable sealing device which seals the wheel in downward direction. Positioned on the tire upper side is an inflation bell having an inflation ring which seals the tire and the rim in upward direction. During inflation, the tire sidewall is urged downwardly by lowering the inflation bell with the inflation ring by a distance causing an annular gap to be produced between the tire bead and the rim through which the compressed air fed into the inflation bell is allowed to enter the tire. When the inflation pressure is reached, the inflation bell is raised, causing the tire sidewalls to move apart in axial direction and the tire beads to occupy their respective seats on the wheel rim.
The tire inflation process described is subject to a variety of influences on which the inflation pressure of the tire depends. Influencing factors include manufacturing-induced dimensional allowances for tire and rim, the tire and rim temperatures, and the soaping condition determining the gliding properties of the tire beads. Rims and tires are also mounted in pairs in a variety of combinations. The tire inflation process and hence the tire pressure may also be dependent on this. In addition to these workpiece-related influences, the inflation pressure of the tires is also determined by influences dictated by the tire inflation device and its control. In practice, however, it is possible only with difficulty to separate the influences of the tire inflation device from those caused by the workpieces, i.e., the tire and the rim.